1. Field of the Invention
The present invention relates to a portable paging telephone system for communicating with a portable telephone set.
2. Description of the Related Art
A mobile telephone terminal unit which accommodates a plurality of base stations in a prior art portable paging telephone system encodes an automobile telephone number or a portable telephone number, that is, a mobile telephone number, pages a telephone number by wireless, accepts a response signal to the paging during a short time period, commands to switch to a channel of the corresponding base station to establish a communication channel, confirms the number and connects the calling station to the paged telephone.
However, unlike the automobile telephone, the portable telephone should be compact and light weight, to facilitate carrying, and the telephone set is folded or an antenna is pushed in a stand-by mode. As a result, during the stand-by of the telephone set, an antenna gain is reduced by approximately 10 dB and a transmission distance is reduced to approximately one half due to a city propagation property of an electromagnetic wave. As a result, a service area may be reduced to one quarter.
A power consumed to watch the paging from a base station amounts to one third of a maximum speech time assuming that the stand-by time is eight hours.
JPA-2-95035 discloses an additional paging system for an automobile telephone set in which a removable paging receiver is attached to a mobile station and when a call from a base station is detected, a call signal is sent to the paging receiver. It can inform the call to a person who moves away from an automobile through the automobile telephone set which has a high receiving capacity, but it cannot be applied to the portable telephone set.